1. Field of the Invention
The present invention relates to the field of video compression, and in particular to a method and apparatus for distributed intraframe transmission.
Sun, Sun Microsystems, the Sun logo, Solaris and all Java-based trademarks and logos are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. All SPARC trademarks are used under license and are trademarks of SPARC International, Inc. in the United States and other countries. Products bearing SPARC trademarks are based upon an architecture developed by Sun Microsystems, Inc.
2. Background Art
Digital video sequences contain large amounts of data. Digital video sequences are typically compressed to increase transmission speed and reduce storage space requirements. One compression technique, known as interframe compression, encodes differences between transmitted frames. Since the difference between temporally close frames is small, less data is required to transmit the differences between two similar frames than to transmit an entire frame. However, as frames become more temporally distant from a reference frame, the differences typically increase. Thus, interframe compression becomes less effective. To reduce the difference between a reference frame and a transmitted frame, a new, complete reference frame, termed an “I-frame,” is transmitted periodically.
Some applications transmit the difference between the transmitted frame and the previous frame. However, errors sometimes accumulate using this technique. In some of these applications, an I-frame is periodically transmitted to compensate for these errors.
I-frames are images encoded without interframe compression (i.e., without reference to any other frame). Thus, it typically requires significantly more data to represent an I-frame than to represent a non-I-frame. In some applications, transmission of I-frames sometimes results in noticeable delays in the digital video transmission. This problem can be better understood by reviewing digital video compression.